In the related arts, a method of preparing d-glucaro-1,4:6,3-dilactone using calcium D-glucarate as a starting material has been suggested. For instance, calcium ions can be separated from a calcium D-glucarate aqueous solution using an expensive ion exchange resin, which is followed by distillation using a solvent such as methyl isobutyl ketone (MIBK). However, the preparation of calcium D-glucarate may cost highly due to complicated process such as material separation and purification in order to increase the purity of the final product. In addition, the expensive ion exchange resin may not be sufficiently reused after recovery, undesirably increasing industrial preparation costs, because calcium salt in the aqueous solution and the oxidation of glucose have to be carried out simultaneously, which reactions do not occur efficiently.
Therefore, it is necessary to develop preparation techniques that are effective and easy and are industrially useful, compared to the aforementioned method.